[Scott H in Wheaton]

Ignition issues sometimes will occur with engine hot that won't occur when engine is cold.
Same with fuel issues.
With the problem getting worse within a short period of time I would suspect fuel. I think ignition parts, if they don't fail all at once, will gradually get worse. Whereas fuel problems can get real bad real quick if you've got water or sediment issues.

I would follow Bubba's Ignition advice and do the condenser. Inexpensive and quick to change compared to the tank, the pump, or the fuel itself.